Caption: Mating body lice. Coloured scanning electron micrograph (SEM) of two human body lice (Pediculus humanus corporis) mating. They are joined at the end of the abdomen (left) and their heads are at right. The male is beneath the female, and is identified by being slightly smaller than the female, and having dark bands across the back. The human body louse lives in clothes and feeds on blood. They are most common in crowded conditions, such as prison camps, where bathing is infrequent and clothes are worn for great lengths of time without changing. They transmit diseases, such as typhus, trench fever and relapsing fever, in their faeces.